Homeostasis
Definition: Ability of systems to regulate their inner environment to reach an equilibrium through physiological processses
Despite change in external environment, living systems will establish equilibrium
Processes:Osmosis, diffusion, active transport (cell membrane)
Osmosis is the movement of molecules from a region of higher water potential to a region of lower water potential across a permeable membrane to achieve dynamic equilibrium


Living organisms obtain and process matter and energy.
E.g. Animals obtain their energy through the food that they consume which their bodies systems will break down glucose in the food and transform it to energy which is needed to carry out life processes. Food is digested and waste is then excreted.
Plants are able to obtain energy through photosynthesis by transforming light energy into energy.

Living organisms use matter and energy to build and maintain body structures
E.g. Milk contains calcium that are used by the young mammals to build bones which maintain body structures. (Young mammals feed on mother's milk)

Energy is stored in the organization of matter
E.g.Mitochondria use glucose to generate energy in the form of ATP

food- fatty acids which joins to form lipids-fats

Energy can be lost but cannot be destroyed. In most processes, energy are usually lost/ wasted as heat energy.

Communities of organisms depend on the cycling of matter and the flow of energy
E.g. water cycle and Carbon cycle

Why is the carbon molecule suitable for life as we know it?
Carbon has a valency of 4 and thus have 4 free electrons to bind with four other atoms and thus it can form macromolecules with different properties and functions. (form carbon backbone)